Lacquer thinner oughta do it. Unless the paint is xylene or epoxy. the stock will probably not return to unpainted color, because there’s always some tiny paint molecules stuck in the pores.
Any of the aforementioned strippers will work. The issue before you now is going to be what you are going to refinish the stock with as the base coat is likely to be affected. On many of the stocks that I have refinished, I just went to sanding, and after smoothing and roughing up the surface, I then applied the new base coat and top coated the stock in whatever pattern that the customers have requested.